Switch governor having perpendicularly pivoted insertable weights



July 7, 1953 E. s. TAMM 2,644,683

SWITCH GOVERNOR HAVING PERPENDICULARLY PIVOTED INSERTABLE WEIGHTS Filed Dec. 2, 1950 3 Sheets-Sheet l m 3a A uvsmoa. Em Ll 5. 722mm ATTORNEY.

July 7, 1953 E. s. TAMM 2,644,683

SWITCH GOVERNOR HAVING PERPENDICULARLY PIVOTED INSERTABLE WEIGHTS 5 Sheets-Sheet 2 Filed Dec. 2, 1950 INVENTOH. [mil .5. Tam/n ATTOHNE Y.

July 7, 1953 2,644,683

E. S.- TAMM SWITCH GOVERNOR HAVING PERPENDICULARLY PIVOTED INSERTABLE WEIGHTS Filed Dec. 2,1950 3 Sheets-Sheet 3 0 xii 1: .1

INVENTOR. Ema! 5. Tamm ATTORNEY.

Patented July 7, 1 953 swrrcrr GOVERNOR HAVING PERPENDICU- I LARLY rrvorsn INSERTABLE -WEIGHTS Emil s. Team, Plainfield, N. J., assignor to The Hoover Company, North Canton, Ohio, at corporation of Ohio Application December 2, 1950, Serial No. 198,816

Claims. (Cl. 264-15) My present invention relates to switch. structures of the type which are commonly used for controlling a phase displaced starting winding in electrical motors of the single phase induction type.

It is a particular object of my invention to provide a centrifugally actuated starting switch for single phase. induction type electrical motors whichis characterized'by high. fidelity in operation, simplicity of fabrication. and assembly, a small number ofparts and in which a single spring element serves to retain certain of the parts in assembled relation, to resist .the centrifugal action of the weight members and to position the parts in closed circuit condition when the motor is inoperative or starting.

It is a further object of my-invention to provide a centrifugalv switch actuating structure composed of a small number of, light-weight sheet metal parts which can readily be stamped into their desired shape and in which the weight members are easily removed for replacement to change the rotational speed at which the starting switch is open circuited and to .allow a single basic structure to be utilized in a plurality of motor designs merely by changing the Weight members, all other parts remaining common to the line.

Other objects and advantages of the invention will become apparent as the descriptionproceeds when taken in connection with the accompanying drawings, wherein: c

Figure 1 is an explodedv view illustrating the parts of my switch actuating mechanism;

Figure 2 isacross-sectional View of a portion of an electric motorillustrating the switching mechanism in the at rest or starting condition thereof; 7

Figure 3 is a view similar to Figure 1 illustrating the switch mechanism in the running position; and

Figure 4 is a sectional view taken on the line l-4 of Figure 3 looking in the direction of the arrows. I

Referring now to the drawing in detail and first to Figure 2 thereof, a split phase, start, single phase run, induction motor is indicated generally at I, having a shaft 2 journalled in suitable bearings mounted in bearing supports 3 in the motor end bells. A starting capacitator is indicated generally at 4 however, the present invention is ap-.

plicable to any type .of motor in which a starting winding or other electrical circuit starting device is energized only during the starting period of the motor and: is then deenergized. In accordance i with usual practice, the end bells of the motor are rigidly secured with the field stack by means of through bolts 5 anchored with nuts 6.

The left hand end of the motor, as viewed in Figure 2, is cut away to illustrate the starting switch construction embodying the present invention.

The starting switch mechanism, indicated generally by the reference character I0, consists of an electric circuit making and breaking part indicated generally at II and stationarily mounted in the end bell in a manner to be described hereinafter, and an actuating section 12 mounted in a manner to be described hereinafter upon the motor shaft 2. The section ll of the switch may be of any desired design. As here shown, it is a leaf spring contact carrying type consisting of a large diameter ring of insulating material I3 having a large central opening through which the shaft 2 extends, and a smaller diameter, heavier rectangular support member It also made of insulating material. The insulating members I3 and I4 are secured to each other and to the end bell of the motor housing by means of studs [6 which are threaded into the end bells in suitable tapped holes and pass through grommets ll of insulating material to space the members I 3 and I 4 in desired relation to each other and to the end wall of the motor housing. The upper end of the insulating support I 4, as viewed in Figures 2 and 4, is provided with a central slot defined by upwardly projecting side wings It. An electrical contact member I9 is mounted on one of the Wings [8 and is connected in any suitable way to a wire 29 which may be connected, for example, in the energizing circuit for the motor starting winding. The member I9 extends into the gap between the members I8 and carries a contact button 2| which is engageable by a complementary contact button 22 mounted upon an upwardly extending arm 23 of a ringshaped leaf spring actuating member 24 positioned around and widely spaced from the shaft 2. The lower end of the ring 24 is provided with two downwardly projecting L-shaped legs 25 of spring material anchored at their ends by means of studs 26 to the lower side portion of the plate I4. vThe leaf spring contact support is bowed at its horizontal center portion to the right as viewed in Figures 1 and 3 and is biased to urge the contact 22 away from the contact 2|, that is, to open circuit position. Movement of the contact 22 in the open-circuit direction, that is, to the right as viewed in Figure 1, to the position shown in Figure 3, is limited by a metal bracket 28 secured 3 to the insulating support I4 and having an end portion extending into the path of movement of the arm 23.

The switch actuating assembly consists of a sleeve 30 having an integral collar 3| on one end thereof provided with a set screw 32 for securing the sleeve rigidly to a shaft. As shown in Figures 2 and 3, the sleeve 30 is mounted on the shaft 2 with the collar 3| in firm engagement with a shoulder 33 formed on the shaft 2 adjacent the rotor field stack indicated at 34. A mounting bracket member 35 is provided with a central web section 36 having a flanged opening 31 press fitted on the sleeve to bring the web 36 into engagement with the collar 3|. The edges of the web 36 are provided with angularly turned flanges 38 extending in the direction of the axis of the sleeve 30 and having outwardly and forwardly extending arms 4|] terminating in angularly bent end portions provided with openings 4|. The angularly bent ends of each pair of arms 4|] lie in common planes which intersect each other and the axis of shaft 2 to the left, Figure 2, of the web section 35. A washer 42, preferably of an insulating material such as a phenol condensation product, is slidably mounted on the sleeve 30 to bear against the free edge of the flange 31. A helical compression spring having a diameter slightly greater than the outside diameter of the flange 31 is mounted around the sleeve 30, the flange 31 and the washer 42, between the web 36 and a plate 45 provided with a central sleeve 46 slidable upon the sleeve 30 within the spring 43. The plate 45 is provided with diametrically opposed, radially projecting curved horns 41 for a purpose to be described hereinafter. The plate 45 is also provided with flanges 48 projecting at right angles to the plate 45, that is, parallel to the axis of the motor shaft, abutting the rear face of a ring 50 of insulating material. The flanges 48 have projecting tongues which extend through suitable openings in the plate 50 and are then riveted over to secure the plate 50 firmly to the flanges 48. The plate 50 is slidably mounted upon the sleeve 30 and is adapted to bear against bearing buttons 55 carried by the spring ring member 24 at diametrically opposite points thereon and at the point of maximum curvature of the ring 24, to the right as viewed in Figures 2 and 3, so as to form the sole means of contact between the plate 5|! and switch structure I0.

Each weight 60 is provided with a pair of projecting tongues 6| extending through the openings 4| in one pair of the angularly bent end portions of the arms 40. The edges of the Weights 60 between the tongues 61 and the faces of the angularly bent end portions of the arms 40 facing the rotor 34 form complementary engaging bearing surfaces on which the weights pivot in operation. The other legs of each of the weight members 60 are provided with rectangular openings 52 which receive the horns 41 on the plate 45. The bias of the spring 43 normally maintains the horns 41 in engagement with the edges of openings 62 remote from the bight portions of the weight members, but the openings 62 are large to allow the plate 45 to be moved manually, to the right as viewed in Figure 2, to disengage the horns 41 from the edges of the openings 62. It is apparent that the bias of the spring 43 urges the horns 41 into firm engagement with the edges of the openings 62, and the force thus applied to the weight members 60 urges the 4 bearing edges thereof into firm engagement with the bearing surfaces on the bracket arms 40. Each weight member 60 is provided with a pair of laterally extending stops 65 which are positioned to move into engagement with stop surfaces 66 on the arms 40. The stops 65 engage the surfaces 63 when the switch is in an at rest position shown in Figure 2. Thus the stops 65 limit the extent to which the spring 43 can move the plate 45 to the left, as viewed in Figure 2; rotation of the weight members toward the axis of the motor shaft is also limited by the stops 65.

In the position of the parts illustrated in Figure 2, the contact buttons 2| and 22 are pressed firmly into engagement with each other to complete the starting winding circuit to the motor. The pressure between the elements 2| and 22 is produced by expansion of the spring 43 pressing the plate 50' into engagement with the buttons 55 and slightly flattening the spring ring 24 after the elements 2| and 22 have contacted each other as the spring 43 is stronger than the bow tension in the ring 24.

When the. motor-is initially energized, the starting winding is energized through the wire 20, contacts 2| and 22, leaf spring structure 23to 25, and wire 61 connected to'one of the arms 25. As the rotor 34 comes up to speed, the centrifugal force acting on the weight members 6|) eventually reaches a value sufficient to overcome the effect of the spring. 43, whereupon the weights swing outwardly about the inturned ends of the arms 40 2.5a pivot to the position shown in Figure 3, drawing the plate 50. out. of engagement with the buttons. 55. Movement of the parts under centrifugal force is limited by engagement of the flange 46 with the stop ring 42. As the plate 50 disengages from the contactv button 55, the leaf spring structure shifts to the position of Figure 3 and separates the contacts 2| and 22 to open the starting winding circuit.

The. switch actuating mechanism may be completely assembled on the sleeve 30 and tested after which thev entire unit may be applied to the shaft 2 and secured by tightening down the set screw- 32'. The sleeve structure 30, 3| and 32 is a preferred embodiment but may be omitted by press, or otherwise, securing the bracket 35 directly on the shaft 2; in this event, the stop washer 42, plate 45 and plate 50 will beslidable directly on the motor shaft 2. Each pair of bearing surfaces formed by the angularlybent ends of the arms 40 faces generally axially of the shaft 2 and, as illustrated; lies in a plane which is angular to the axis of the shaft 2. The bearing surfaces on the horns 41 and arms generally face axially of the shaft 2 in opposite directions; the same relationship obtains between the respectively corresponding bearing surfaces on each of the weights 60 wherefore the spring 43 maintains all these surfaces in contact. The tongues 5| and openings 4| serve to limit movement of the weights radially of the shaft 2 but are readily separable by relative movement generally axially of the shaft 2.

The present switch structure is particularly designed to be applicable to a plurality of motors having different speed characteristics simply by altering. the. weight members 60. The weight of these members can beincreased by mounting lead inserts in the slots 10"formed in the bight portions of the members 50. In the case of motors having connections for variable. speed operation to be made at the will of the consumer,. the weight members 50 are readilyremovableifrom the other:

elements of the switch actuating structure in order to increase or decrease their mass by adding or removing inserts in the slots 10. In order to remove the weight members 60 without completely disassembling the switch actuating mechanism as a whole, the parts are moved to the position illustrated in Figure 3 by applying pressure to the plate 50. When this is accomplished, the weights 6B are readily removable by withdrawing the tongues 61 from the openings 41 after which the weights can be removed by sliding the same off the horns 41. The weights can be replaced by reversing the foregoing process.

The present construction provides a switch actuator which is light in weight, sure in operation, inexpensive to manufacture, has a minimum number of parts and is assembled and disas= sembled with great facility without the use of special tools.

I claim: 7

1. In a centrifugal switch, an actuating mechanism comprising a sleeve member adapted to be secured to a rotatable shaft, a bracket secured to said sleeve and provided with pairs of spaced parallel arms extending from opposite sides thereof, each pair of said arms having end portions turned inwardly toward each other and provided with openings, a plate slidably mounted on said sleeve and provided with diametrically opposed projecting tongues, a compression spring mounted between said bracket and said plate, a pair of weight members each having a pair of projections engaging in the openings of one of said pairs of arms and an opening receiving one of said tongues, and stop means on said weights engageable with said bracket to limit movement of said plate on said sleeve by said spring.

2. In a centrifugal switch, an actuating mechanism comprising, a shaft member, a bracket on said shaft member, a plate slidably mounted on said shaft member and carrying a switch actuating member, a compression spring encompassing such shaft member between said bracket and said plate and urging said plate to move away from said bracket, arms on said bracket extending outwardly thereof and arranged in spaced pairs, the arms forming each of said pairs having their ends turned inwardly toward each other in a common plane transverse to the axis of said shaft member to provide bearing surfaces, each of the turned ends of said arms being formed with openings, a plurality of U-shaped weight members, each of said weight members having one end of one leg thereof bearing on one pair of said bearing surfaces and having projections extending through the openings in said pair of bearing surfaces, the other leg of each of said weight members being formed with an opening, and a plurality of radial- 1y extending tongues on said plate curved axially of said shaft member away from said bracket and each extending through the opening in one of said weight members a lesser distance from said shaft member than said bearing surfaces whereby the force of said spring maintains said weight members in engagement with said bearing surfaces.

3. Apparatus according to claim 2 in which said weight members are provided with laterally extending tongues positioned to engage said arms and limit movement of the bight portions of said weight members toward said shaft member and movement of said plate away from said bracket under the force of said spring.

4. In a centrifugal switch, a shaft member, a bracket fixedly mounted on said shaft member, said bracket having spaced pairs of diametrically opposed arms projecting therefrom outwardly of said shaft, the arms of each of said pairs having spaced flat parallel portions terminating in bearing portions extending toward each other and 1ying in planes intersecting the axis of said shaft. a plate slidably mounted on said shaft and carrying a switch actuating member, a spring biasing said plate away from said bracket axially of said shaft, a pair of U-shaped weight members each lying between one of said pairs of arms and having an outer leg bearing on the bearing por tions of said one of said pair of arms and having projecting tongues extending through openings in said bearing portions, said plate having a pair of diametrically opposed projections extending outwardly of said shaft and each being dimensioned and positioned to pass between one of said spaced pairs of arms when said plate is moved by said weights axially of said shaft against the bias of said spring, and the inner leg of each of said weights having an opening receiving one of said projections.

5. A centrifugal switch actuating mechanism comprising a sleeve adapted to be removably secured on a driving shaft, a bracket fixed to said sleeve in spaced relation to one end of said sleeve, a plate slidably mounted on said sleeve, a spring around said sleeve bearing between said bracket and said plate and biasing said plate away from said bracket toward sai one end of said sleeve, a plurality of weight members pivotally mounted on said bracket and extending away from said plate and each of said weight members having a part lying radially inwardly of its pivotal connection to said bracket and pivotally connected to said plate whereby to draw said plate toward said bracket as said weights respond to centrifugal force, and stop means on said weights and said bracket limiting movement of said plate toward said one end of said sleeve by said spring.

EMIL S. TAMM.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,580,161 Persons Apr. 13, 1926 1,897,405 Thompson Feb. 14, 1933 1,926,339 Kindl Sept. 12, 1933 2,095,755 Libby Oct. 12, 1937 2,416,973 Wright Mar. 4, 1947 2,512,405 Willits June 20, 1950 2,538,410 Bretch Jan. 16, 1951 2,544,791 Hunt Mar. 13, 1951 2,573,968 Hammell Nov. 6, 1951 

